<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 80%;
            height: 400px;
            background-color: pink;
            /* 让三个子盒子同时在侧轴低侧对齐 */
            /* align-items: flex-end; */
            /* 我们只想让第三个盒子低侧对齐 */
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: skyblue;
            margin-right: 5px;
        }

        div span:nth-child(3) {
              /* align对齐 self自己   第三个子项 侧轴 低侧 对齐 */
            align-self: flex-end;
        }
        div span:nth-child(2) {
            /* order 定义子项的排列顺序 数值越小位置越靠前 默认是0 -1比0小 所有在前面 */
            order: -1;
        }
    </style>
</head>

<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>

</html>